UTILIZATION OF SPHERICAL CRYSTALLIZATION TECHNIQUE IN THE PREPARATION OF SUSTAINED-RELEASE FUROSEMIDE TABLETS

Furosemide microcapsules were prepared by a spherical crystallization technique using acrylic polymers (Eudragit RS 100 and RL 100). The microcapsules obtained were spherical with a mean particle diameter of 500 and 580 mu m for Eudragit RS and RL respectively. The microcapsules were tabletted, and the physical characteristics of the tablets were related to the microcapsule size, core/wall ratio and to the storage at humid atmosphere (40 degrees C, 90% relative humidity). In vitro dissolution studies in phosphate buffer (pH 7.4) showed that the most retardant effect was obtained by using larger microcapsules, lower core/wall ratio and Eudragit RS. On the other hand, storage did not affect the amounts of furosemide released from tablets prepared from Eudragit RS microcapsules after 20 to 30 min with a slight decrease in the initial rate of release. Dissolution data showed that the release followed Higuchi matrix model kinetics.